Well pumps for abrasive fluids



July 23, 1963 E. L. DAVIS wan. PUMPS FOR ABRASIVE mums Filed July 21, 1961 Fire. I

mmvron. 2 654: 1.. fin ws W a Arra E/VEYS ted rates Filed July 21, 1961, Ser. No. 125,831 6 Claims. (Cl. 193-165) This invention relates to well pumps for abrasive fluids and included in the objects of this invention are:

First, to provide a well pump for abrasive fluids in which the column of abrasive well fluids being pumped is counterbalanced by non-abrasive fluid and a mechanical reciprocating pump operates in the environment of the non-abrasive counterbalancing fluid to pump the abrasive fluid, and a barrier of non-abrasive fluid is maintained between the reciprocating pump and the abrasive well fluid.

Second, to provide a well pump of this type wherein the column of non-abrasive fluid may, by reason of its density or by reason of pressure applied at the well mouth, overcounterbalance the column of well fluid, and the mechanical pump may be so arranged as to permit a controlled leakage of the non-abrasive fluid into the column of well fluid.

Third, to provide a well pump of this type in which the non-abrasive fluid may be caused to surge back and forth or to flow through the reciprocating pump and discharge with the abrasive well fluids for purposes of flushing the system or to introduce emulsion breaking fluids, or to lubricate particularly if the well fluid lacks lubricating properties, or to introduce plating chemicals which coat the parts for corrosion protection.

Fourth, to provide a well pump of this type in which the sucker rod string used to reciprocate the mechanical pump is maintained under the tension by the counterbalancing fluid to protect the sucker rod string.

With the above and other objects in view as may appear hereinafter, reference is directed to the accompanying drawings, in which:

FIGURE 1 is a diagrammatical view of the well pump for abrasive fluids showing both the sub-surface equipment and the surface equipment.

FIGURE 2 is an enlarged diagrammatical view of the sub-surface equipment of the well pump for abrasive fluids with the portions broken away and in section to facilitate the illustration.

The well pump for abrasive fluids includes a Well pump conduit 1 which extends from the mouth of the well to the pumping level thereof. A counterbalancing fluid conduit 2 also extends from the mouth of the well to the pumping level. The two conduits are joined by a bottom connection 3. The lower portion of the Well fluid conduit 1 is enlarged to form a well fluid collecting chamber 4.

Located near the upper end of the well fluid collecting chamber 4 is an intake valve 5 communicating with inlet side port 6. Above the intake valve 5 is a discharge valve 7. The intake valve 5 is so arranged that well fluids may be drawn into the collecting chamber 4 and are trapped by the intake valve against back-flow into the well bore. This discharge valve 7 is so arranged that well fluid may pass upwardly from the collecting chamber 4 into the well fluid conduit 1 thereabove, but is prevented from backflow from the conduit 1 into the collecting chamber 4.

The lower end of the counterbalancing fluid conduit 2 forms a plunger chamber 8 which for convenience of illustration is shown as larger than the counterbalancing fluid conduit but which, in fact, may be equal in diameter. Reciprocally mounted within the plunger chamber 8 is a plunger 9 which may, in fact, be a conventional bottom hole pump, or the pump body or a bottom hole pump. Essentially the plunger is a tubular member which may, or may not, include packing means to form a seal between the plunger and the walls of the plunger chamber. It is 3:,fl98A5Z Patented July 23, 1963 desirable but not necessary to the operation of the plunger that there be provided a pre-loaded check valve 10. More particularly, the check valve 10 is backed by a spring 11 which permits the check valve to open only when the pressure above the check valve exceeds the pres sure below the check valve by a predetermined value.

The plunger 9 is connected to a sucker rod string 12 which extends through the counterbalancing fluid conduit 2 to the mouth of the well and projects through a conventional packing gland 13. The sucker rod string is adapted to be recipro-cated by conventional pump operating means, not shown.

Located at the well mouth is a pressure vessel 14 which is joined to the counterbalancing fluid conduit 2 by a connecting line 15 in which is interposed a by-pass line 16. A gate valve 17 is located in the connecting line 15 and a check valve 18 is located in the by-pass line 16. The gate valve, when opened, permits flow in either direction. The check valve permits flow only from the pressure vessel 14 to the counterbalancing fluid conduit 2.

The pressure vessel 14 is adapted to be partially filled with a counterbalancing fluid which also fills the conduit 2. The level of the counterbalancing fluid is maintained by a float valve 19 which controls a counterbalancing fluid inlet 20. The upper end of the pressure vessel is also provided with a pressure fluid inlet 21. The pressure fluid may be a pressurizing gas.

Operation of the well pump for abrasive fluids is as follows: One method of operation consists in introducing into the counterbalancing fluid conduit 2 a counterbal ancing of fluid which has a greater specific gravity than the well fluid. As a consequence its pressure at the plunger chamber 8 exceeds the pressure of the well fluid at the discharge valve 7. Assuming that the check valve 10 is omitted, the plunger 9 may be so constructed as to permit a controlled amount of leakage of counterbalane ing fluid whereby the counterbalancing fluid which leaks past the plunger tends to fill the bottom connection 3 and the lower end of the collecting chamber 4 to form a barrier between the well fluid collecting chamber 4 and the plunger 9.

When the plunger 9 moves in its upward stroke, the well fluid intake valve 5 is caused to open admitting well fluid to the collecting chamber 4-. When the plunger 9 is moved downward, the collected well fluid is forced upwardly through the discharge valve 7 into the well fluid conduit 1. The well fluid with the addition of whatever counterbalancing fluid may have leaked past the plunger 9 is discharged from the upper end of the well fluid conduit 1.

With the arrangements thus described, the pressure vessel '14 need not be used; however, it is desirable to maintain an excess quantity of counterbalancing fluid at the mouth of the well but not necessarily under pressure.

If it is desired to use a counterbalancing fluid which may not have a density equal to the well fluid, the pressure vessel .14 is utilized to permit the application of a supplementing gas pressure so that the effective pressure at the plunger 9 exceeds that of the well fluid at the discharge valve 7.

It should be noted that the gate valve 17 is normally opened so that as the plunger 9 reciprocates, the counterbalancing fluid may surge back and forth. 'It will also be observed that a force is applied to the upper end of the plunger 9 equal to the weight of the column of counterbalancing fluid. This has the effect of applying tension to the sucker rods so that at no time is the sucker rods subjected to compression loads. This is highly desirable for the presence of compressive loads would tend to kink, or in any case, subject the sucker rods to destructive stresses.

It is desirable from time to time to flush the entire pump system, and this maybe accomplished by closing the gate valve 17 so that the counterbalancinig fluid is actually pumped by the plunger 9, the pressure fluid flowing past the check valve 10. When the flushing operation is performed, little or no well fluid enters so that eventually the counterbalancingfluid is forced down the conduit 2 and out the well fluid conduit 1.

The counterbalancing fluid may be water or water with various additives, for example, the counterbalancing fluid may contain emulsion breaking chemicals or lubricants, or various plating chemicals, which when caused to flow over the parts of the sub-surface equipment tends to plate or coat the parts against corrosion. The counterbalancing fluid may be a lubricating oil or a fluid mixture including lubricating oil.

1 It will be observed'that by reason of the.'counterbalancing fluidconduit, the location of the plunger in this conduit rather than in the well fluid conduit, and a provision of means whereby fluid from the counterbalancing conduit forms a barrier between the well fluid and the plunger, that the plunger is completely protected against damage from the well fluid. The only parts which are subject to the action of the Well fluid are in intake valve and the discharge valve 7. These valves may be simple ball I check valves and inherently capable of withstanding a substantial amount of abuse, much more so than the relatively sliding walls of the plunger 9 and plunger chamber 8. As a consequence, the pump is particularly adapted to the pumping of'well fluids which may contain abrasives or corrosive material.

It will be noted that, as shown in FIGS. 1 and 2, the bottom connection -3 is made smaller'in diameter than'the diameter of the plunger chamber Sand the fluid collecting chamber 4 to cause higher flow velocity therein, thereby to sweep into the collecting chamber 4 any sand which may collect in the bottom connection 3 between pumping strokes.

Having fully described my invention, it is to be, under-' stood that Ido not wish to be limited to the details herein set forth or to the details illustrated in the drawings, but my invention is of the full scope of the appended claims.

I claim:

.1. A well pump, comprising:

(a) a well fluid conduit;

(b) a counterbalancing fluid conduit;

(c) both of said conduits extending from the mouth to the pumping level of a well;

'(d) means forming aplunger chamber at the lower end of the counterbalancing fluid chamber;

(e) means forming a well fluid collecting chamber having an upper end above the lower end of said plunger chamber; 7

(f) a connecting tube joining the lower ends of said chambers;

(g) a well fluid inlet valve disposed in said fluid co llecting chamber above the lower end of said plunger chamber; 7

(h) a discharge valve above said inlet valve for admitting fluid into said well fluid conduit from said fluid collecting chamber;

(i) a reciprocable plunger in said plunger chamber;

(j) a string of sucker rods extending therefrom to the mouth of the well to reciprocate said plunger thereby to draw well fluid into said collecting chamber and expel fluid through said well fluid conduit;

(k) and a counterbalan'cing fluid in said counterbalancing conduit supported by said plunger.

5 2. A well pump as set forth'in claim 1, wherein:

(a) said connecting tube has a smaller cross section than said well fluid receiving chamber and said plunger chamber to cause high velocity flow therethrough.

10 3. A well pump for abrasive fluids as set forth in claim 1, wherein: the counterbalancing fluid has a greater density than the well fluid whereby its pressure at the plunger is greater than the well fluid, and tends to leak past the plunger to form a barrier between said plunger and said well fluid.

4. A well pump for abrasive fluids as set forth in claim 1, wherein: a container for excess counterbalancing fluid is provided at the well mouth, and connected with said counterbalancing fluid conduit to permit surging of said counterbalancing fluid as said plunger is reciprocated.

5. A well pump for abrasive fluids as set forth in claim 1, wherein: said counterbalancing fluid has a lesser density than said well fluid; a pressure container for excess counterbalancing fluid is connected with the month end of said counterbalancing fluid conduit and the excess counterbalancing fiuid therein is subjected to a pressure to raise the pressure at said plunger above the pressure of said well fluid, thereby to cause movement of said counterbalancing fluid past said plunger to form a barrier between said plunger and said well fluid.

6. A well pump, comprising:

(a) a conduit for well fluids;

(b) a conduit for counterbalancing fluids, both of said conduits extending from the mouth to the pumping level of a well; 7 I

(c) means forming a wellfluid collecting chamber connecting the lower ends of said conduits;

(d) a first valve for admitting well fluid into said chamber;

(e) a second valve for admitting well fluid from said chamber to said well fluid conduit;

(f) a reciprocable'plunger at the bottom of said counterbalancing fluid conduit, said plunger having a first check valve permitting downward flow of fluid therethrough;

(g) a string of sucker rods extending therefrom to the mouth of the well to reciprocate said plunger thereby to draw well fluid into said collecting chamber and expel fluid through said well fluid conduit;

(h) a counterbalancing fluid'in said counterbalancing conduit supported by said plunger;

(i) V a container for excess counterbalancing fluid at the well mouth and connected with said counterbalancing conduit;

(j) and a second check valve interposed between said container and said counterbalancing fluid conduit to prevent back flow of said counterb alancing fluid;

(k) said first and second check valves and said plunger cooperating to pump said counterbalancing fluidinto said well fluid conduit to flush said well fluid conduit.

1,497,326 Van Keulen June 10, 1924 

1. A WELL PUMP, COMPRISING: (A) A WELL FLUID CONDUIT; (B) A COUNTERBALANCING FLUID CONDUIT; (C) BOTH OF SAID CONDUITS EXTENDING FROM THE MOUTH TO THE PUMPING LEVEL OF A WELL; (D) MEANS FORMING A PLUNGER CHAMBER AT THE LOWER END OF THE COUNTERBALANCING FLUID CHAMBER; (E) MEANS FORMING A WELL FLUID COLLECTING CHAMBER HAVING AN UPPER END ABOVE THE LOWER END OF SAID PLUNGER CHAMBER; (F) A CONNECTING TUBE JOINING THE LOWER ENDS OF SAID CHAMBERS; (G) A WELL FLUID INLET VALVE DISPOSED IN SAID FLUID COLLECTING CHAMBER ABOVE THE LOWER END OF SAID PLUNGER CHAMBER; (H) A DISCHARGE VALVE ABOVE SAID INLET VALVE FOR ADMITTING FLUID INTO SAID WELL FLUID CONDUIT FROM SAID FLUID COLLECTING CHAMBER; (I) A RECIPROCABLE PLUNGER IN SAID PLUNGER CHAMBER; (J) A STRING OF SUCKER RODS EXTENDING THEREFROM TO THE MOUTH OF THE WELL TO RECIPROCATE SAID PLUNGER THEREBY TO DRAW WELL FLUID INTO SAID COLLECTING CHAMBER AND EXPEL FLUID THROUGH SAID WELL FLUID CONDUIT; (K) AND A COUNTERBALANCING FLUID IN SAID COUNTERBALANCING CONDUIT SUPPORTED BY SAID PLUNGER. 